ENGINE VEHICLE EQUIPPED WITH VARIABLE DISPLACEMENT HYDRAULIC PUMP FOR VARIABLE SPEED CONTROL

摘要

PURPOSE:To obtain various kinds of feeling in operating a vehicle using a small number of solenoid valves and also to achieve miniaturization of a hydraulic control circuit and reduction in the manufacturing cost of the circuit. CONSTITUTION:An orifice 13 is connected to a line 16a which connects the front room 63a of a servo cylinder 63 to a directional control valve 10 and poppet valves 11 are connected in parallel at both ends of the orifice 13. A poppet valve 12 is connected between that portion of the line 16a which is located on the lower side of the poppet valves 11 and a line 16b which connects the rear room 63b of the servo cylinder 63 to the directional control valve 10. Both of the poppet valves 11, 12 which constitute a servo pressure setting circuit are duty controlled by a controller 14 and desired servo pressure is supplied to the servo cylinder 63.